In a vehicle having an electrically actuated clutch, it is desirable to be able to provide a fail safe operation mode for the clutch in the event of a power loss, such as a system power loss for supplying power to the clutch actuator. In the event of a power loss when the vehicle is stationary with the clutch disengaged or open and with the engine running, it is desirable to ensure that a power loss does not cause the clutch actuator to engage or close the clutch, which may result in the vehicle lurching forward.
Alternatively, if a power loss occurs when the vehicle is moving and the electrically actuated clutch has been disengaged, such as in the middle of a gear shift, it is desirable for the clutch to move to an engaged position. For example, when a vehicle is traveling downhill, it is desirable to provide engagement of the clutch during a power loss condition to connect the drive wheels to the engine in order for engine braking to facilitate slowing the vehicle. In such a situation, the clutch must be capable of being actuated to move from a disengaged position to an engaged position.
Accordingly, it can be seen that two opposite conditions of the clutch are required for a vehicle system power loss condition, depending on the operating state of the vehicle.